The cts-attrd, cts-fencing, and cts-exec regression tests run Corosync. That can be a problem if tests are run on more than one node in a cluster at the same time (for example, cts-fencing assumes no other node besides the local one will respond to fence queries).

The tests use the APIs in python/pacemaker/_cts/corosync.py. The APIs currently use any existing corosync.conf if present, otherwise they generate a new (single-node cluster) config. If there is an existing corosync.conf, we should temporarily rename it, generate a new config, and move the original one back when done.

Note that cts-lab uses cmcorosync.py instead of corosync.py, so it should be unaffected.